Electrical contact-brush and method of producing same.



PATENTED MAR. 10, 1903.

v H. N. MOTSINGER. ELECTRICAL CONTACT BRUSH AND METHOD OF PRODUCINGSAME.

APPLICATION FILED AUG. 25, 1902.

r0 MODEL.

IKK i I K K K I K I! INK i l X I K K X I K I N I I l i K K KI 7 I I I Ii i h i i I I II IN VE N 70/? Homer N.Motsinger A TTOBNE m f WITNESSES WMourns P UNIT D STATES PATENT OFFICE.

HOMER N. MOTSINGER, OF PENDLE'ION, INDIANA, ASSIGNOR TO MOTSINGER DEVICEMANUFACTURING COMPANY, OF PENDLETON, INDIANA, A COR- PORATION OFINDIANA.

ELECTRICAL CONTACT-BRUSH AND METHOD OF PRODUCING SAME.

SPEGIFIGATION forming part of Letters Patent No. 722,606, dated March10, 1903.

Application filed August 25, 1902.

To all whom it may concern:

Be it known that 1, HOMER N. MOTSINGER, a citizen of the United States,residing at Pendleton, in the county of Madison and State of 5Indiana,haveinvented certain new and useful Improvements in ElectricalContact-Brushes and Method of Producing Same, of which the following isa specification. '1

The object of my invention is to producea IO composite contact-brushformed of metal and carbon inwhich the carbon forms a central coreprotected by an external shell of metallic gauze, the arrangement beingsuch that the gauze serves as a binder or containingr 5 shell for thecarbon, so that any distortion of the brush due to external pressureexerted by a holder cannot disintegrate the carbon insuch manner as tocause it to separate from the metal, the brush thus formed being par- 20ticularly adapted for use in hollow holders,

so that a'bimetal contact may be secured between the brush and holderinstead of a contact between the metal of the holder and the carbon, asis the casein that class of brushes 2 5 where a metallic core isembedded in a shell of carbon.

A further object of my invention is to provide a method of producing myimproved brush by means of which the external wrapping of gauze may besecured to the carbon in such manner that it may not become displaced.

The accompanying drawings illustrate my invention.

Figure 1 is an enlarged longitudinal sectionof a desirable form. Fig. 2is a side elevation of the form shown in Fig. 1, in which the gauze orwrapping is laid on straight. Fig. 3 is a view similar to Fig. 2,showing the gauze 4o laid on bias. Fig. 4. is a section on line 4 4.

in Fig. 2; and Fig. 5 is a side elevation, full size, of a brushparticularly designed for small machines.

The brush consists of a central core 10, of

45 carbon or similar conducting material. Wrapped about the core is asheet or portion of gauze 11, the ends of which are secured together inany suitable manner, as by solder 12, so as to hold the gauze about thecore. If

Serial No. 120,928. (No model.)

desired, the core 11 may first be provided with a thin shell of material13, preferably applied electrolytically in the ordinary manner.

In order to make a successful and .commercial brush, it is essentialthat the wrapping be so positively secured to the core that it may notbecome readily displaced, and in order to accomplish this result I haveadopted the following method:

Strips of gauze are out which in width are somewhat less than thecircumference of the core 10, and these strips are then heated so as tocause expansion thereof, the transverse strands of the gauze expandinglongitudinally so as to increase the width of the strips. These stripswhile heated are then rolled about the core 10, the edges coming closetogether and being secured by any suitable means-such, for instance, asa connectingbar of solder 12which becomes intimately united with theadjacent edges of the gauze. When this is accomplished, the resultantcontraction of the gauze, due to cooling, clamps the gauze shell tightlyabout the core, so that the shell becomes intimately associated with thecore and cannot be readily displaced. If the core has been preliminarilyprovided with an electrolytic coacting of copper 13, the solder ofcourse sticks to this core. By forming a brush in this manner,especially in the cylindrical form shown, it may be readily insertedinto a tubular holder and a metallic contact obtained throughout thelength of the periphery of the brush with the holder. If desired, ametal cap 14. may be secured to the outer end of the brush andintimately connected with the wrapping of the gauze, as shown in Fig. 3,if desired. Any 'external pressure unequally applied to the periphery ofa brush formed in this manner will have less tendency to crack thecarbon than in a case where the carbon forms an external metallic gauzethe edges of which are brought together and connected by solder.

2. A contact-brush consisting of a central core of carbon, a shell orcasing of electrolytic metal, and an external wrapping of gauze.

3. A contact-brush consisting of a central core of carbon, a shell orcasing of electrolytic metal, and an external wrapping of gauze theedges of which are brought together and secured by solder.

4. A contact-brush consisting of a central core of carbon, and anexternal shell or gauze shrunk upon the core.

